Fix the section of notify_on_state_change to [notifications]
Fix the section of notify_on_state_change to [notifications]

https://github.com/openstack/nova/blob/042f08ee968fc83b80e554efe58270c8dfd6265c/nova/conf/notifications.py#L41

Change-Id: Ic09b05e3b4603f5967a2ee67191b931661ef8fe0
Closes-Bug: #1800674

openstack/ceilometer,openstack/ceilometer